Two-pore-domain potassium channels: This family of 15 members form what is known as "leak channels" which possess Goldman-Hodgkin-Katz (open) rectification.[1] These channels are regulated by several mechanisms including oxygen tension, pH, mechanical stretch, and G-proteins. Their name is derived from the fact that the α subunits consist of four transmembrane segments, each containing two pore loops. As such, they structurally correspond to two inward-rectifier α subunits and thus form dimers in the membrane.